Flood — Taiya Inlet, Alaska

2022-10-01 · near Skagway, Taiya Inlet, Alaska

Event narrative

The water levels along the Taiya River were receding from a previous rain event that produced some minor flooding on September 29th and was near to just below bankful levels by the afternoon hours of September 30th. Moderate to heavy rain along with very warm temperatures associated with a strong atmospheric river moved over the northern inner channels of Southeast Alaska through the overnight hours going into October. The strong low level winds along with abundant sub-tropical moisture being transported over the complex terrain of the region produced very high rain amounts with 1.5 to 2 inches falling in 18 hours across the headwaters of the Taiya River basin. The combination of the heavy precipitation along with ice melt from the glaciers in the headwaters caused significant amount of runoff into the Taiya River. The Taiya River rose rapidly through the overnight hours and was above moderate flood stage of 17 feet right after midnight on October 1st. The river continue to rise at a rapid rate and crested in the mid morning at 19.38 feet. This was the third highest crest at the time. There was significant amount of flooding along the Chilkoot trail and in the town of Dyea. The National Park Service campground in Dyea was closed from flood waters inundating the entire area along with water surrounding the NPS ranger station. There was significant amount of flooding of the roads going to the Dyea historic site from culverts being overwhelmed, Dyea Road near the McDermott Road turnoff had at least 6 inches of water over the road which is just past the Taiya River bridge. There was a lot of damage to NPS infrastructure along the Chilkoot trail, Dyea campground and roads around Dyea. This was one of the most impactful flooding events that the areas has seen in almost 20 years.

Wider weather episode

Southeast Alaska had been impacted by a number of atmospheric rivers through September to keep streamflow on small and large rivers high. Another atmospheric river lifted out of the north Pacific as the associated warm front moved over Southeast Alaska it produced heavy rain over the northern inner channels of the panhandle. The front also advected a lot of warm air with freezing levels near 10 thousand feet. The complex terrain of the region enhance the rainfall with 1.5 to 3.5 inches of rain fell over a 12 to 18 hour period.

The heavy rain and significant ice melt from the very warm temperatures in the headwaters of the Taiya River produced a lot of overland flow. This caused moderate flooding along the Taiya River from the early morning hours to the late afternoon on October 1st. There was road closures, damage to National Park Service infrastructure along the Chilkoot trail and near the Dyea campground. This was also the 4th highest peak flood on record. There was also moderate flooding along Jordan Creek in Juneau from the early morning to the afternoon hours on October 1st. The crested was the 2nd highest peak flood on record. A large landslide along the Haines Highway around 23 mile that came down in the overnight hours of October 1st and blocked the road. The area around the landslide reported 1 to 1.5 inches of rain in 12 hours.

View location on OpenStreetMap → (59.4819, -135.3390)

Source: NOAA Storm Events Database, event_id 1061470. Narrative written by the NWS forecast office that issued the report.